A New Method Using the Four‐Chamber View to Identify Fetuses With Subsequently Confirmed Postnatal Aortic Coarctation

ABSTRACT Objective To determine the sensitivity, specificity, and false‐positive rate among fetuses suspected prenatally to have coarctation of the aorta (CoA) using size and shape measurements of the fetal heart from the four‐chamber view (4CV). Methods This was a retrospective study of 108 fetuses identified by pediatric cardiologists to be at risk for CoA. 4CV s from the last antenatal ultrasound performed by the cardiologists were analyzed. The end‐diastolic area was computed using the point‐to‐point trace method around the epicardial border of the 4CV, and the largest end‐diastolic length and width were measured from the epicardium to the epicardium to compute the global sphericity index (GSI) (length/width). Using speckle tracking analysis, the ventricular end‐diastolic area, length, basal and mid‐chamber widths were measured. The sphericity index of the base and mid‐chamber of the ventricles was computed (length/width). In addition, the end‐diastolic area ratios were computed as follows: right ventricular area/4CV area and the left ventricular area/4CV area. The z ‐scores for the above measurements were computed. Using logistic regression analysis, coefficients for predicting the probability of CoA from a test group of 27 fetuses with CoA and 27 without CoA was done. The logistic regression equation derived from the test group was applied to a validation group of 27 fetuses with CoA and 27 fetuses without CoA. Results The regression equation from the test group identified the following end‐diastolic measurements: 4CV GSI, RV area/heart area, LV base SI, and the RV Base SI. The test group consisted of 14 of 27 fetuses with an isolated CoA (52%) and 13 of 27 (48%) with additional heart abnormalities. For the validation group, 10 of 27 (37%) had an isolated CoA, and 17 (63%) had additional cardiac abnormalities. Using the logistic regression equation derived from the test group (54 fetuses: 27 with CoA and 27 without CoA), the validation group (54 fetuses: 27 with CoA and 27 without CoA) demonstrated the following: sensitivity for detecting CoA of 98.15%, specificity 98.15%, and a false‐positive rate of 1.85%. When the logistic regression was applied to the test group of fetuses with isolated CoA, 100% (14/14) were identified with logistic regression analysis. For the validation group, 9 of 10 (90%) of fetuses with isolated CoA were identified using the logistic regression equation. Conclusions Using length, width, and area measurements of the 4CV and ventricles from which ratios are computed detects 98.15% of high‐risk fetuses who will demonstrate CoA following birth, with a specificity of 98.15%, or a false‐positive rate of 1.85%.